Start this recipe by quickly pan frying the chicken breast on both sides to seal in their juices. Remove off the heat and allow to cool. Mix together the grated Parmesan, almonds, herbed breadcrumbs in a large plate and season well with salt and pepper. Spread each chicken breast liberally on both sides with a tablespoon of mayonnaise per breast, coating all over. Dip the chicken into the breadcrumb mixture, coating well in the crumbs. Place the chicken breasts on a baking tray and continue to cook in the oven at 200`c for 10-15 minutes, or until cooked through. Next, soak the dried porcini mushrooms in 200ml hot water for 10 minutes until they have softened. Heat the oil and butter in a large, heavy based frying pan and add in the onion, garlic, celery and thyme. Fry over a gentle heat for 3-4 minutes, or until the onion has softened. Stir in the Arborio rice and coat each grain in the oil in the pan. After a minute or so, pour in the white wine, stirring until the liquid has been completely absorbed. Season the rice well with salt and pepper. Add in the water from the porcini mushrooms, along with a ladleful of the stock, stirring again until the liquid has been absorbed. Continue adding the stock in this way, until all the liquid has been absorbed and the rice is plump and almost cooked. Roughly chop the soaked porcini mushrooms and stir into the risotto, along with the sliced chestnut mushrooms and the parsley. Cook the risotto for just a few more minutes to cook the mushrooms before stirring in the mascarpone cheese. Serve the risotto in large plates with the crusted chicken breasts on top and a few dress rucola leaves.